<div class="slideshow-container">

   <div class="mySlides fade">

     <div class="numbertext">1 / 3</div>

     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_mountains_wide.jpg" style="width:100%">

     <div class="text">文本 1</div>

   </div>

   <div class="mySlides fade">

     <div class="numbertext">2 / 3</div>

     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_fjords_wide.jpg" style="width:100%">

     <div class="text">文本 2</div>

   </div>

   <div class="mySlides fade">

     <div class="numbertext">3 / 3</div>

     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_nature_wide.jpg" style="width:100%">

     <div class="text">文本 3</div>

   </div>

 </div>

 <br>

 <div style="text-align:center">

   <span class="dot"></span>

   <span class="dot"></span>

   <span class="dot"></span>

 </div>

 * {box-sizing:border-box}

 body {font-family: Verdana,sans-serif;}

 .mySlides {display:none}

 /* 幻灯片容器 */

 .slideshow-container {

   max-width: 1000px;

   position: relative;

   margin: auto;

 }

 /* 下一张 & 上一张 按钮 */

 .prev, .next {

   cursor: pointer;

   position: absolute;

   top: 50%;

   width: auto;

   margin-top: -22px;

   padding: 16px;

   color: white;

   font-weight: bold;

   font-size: 18px;

   transition: 0.6s ease;

   border-radius: 0 3px 3px 0;

 }

 /* 定位 "下一张" 按钮靠右 */

 .next {

   right:;

   border-radius: 3px 0 0 3px;

 }

 /* On hover, add a black background color with a little bit see-through */

 .prev:hover, .next:hover {

   background-color: rgba(0,0,0,0.8);

 }

 /* 标题文本 */

 .text {

   color: #f2f2f2;

   font-size: 15px;

   padding: 8px 12px;

   position: absolute;

   bottom: 8px;

   width: 100%;

   text-align: center;

 }

 /* 数字文本 (1/3 等) */

 .numbertext {

   color: #f2f2f2;

   font-size: 12px;

   padding: 8px 12px;

   position: absolute;

   top:;

 }

 /* 标记符号 */

 .dot {

   cursor:pointer;

   height: 13px;

   width: 13px;

   margin: 0 2px;

   background-color: #bbb;

   border-radius: 50%;

   display: inline-block;

   transition: background-color 0.6s ease;

 }

 .active, .dot:hover {

   background-color: #717171;

 }

 /* 淡出动画 */

 .fade {

   -webkit-animation-name: fade;

   -webkit-animation-duration: 1.5s;

   animation-name: fade;

   animation-duration: 1.5s;

 }

 @-webkit-keyframes fade {

   from {opacity: .4}

   to {opacity:}

 }

 @keyframes fade {

   from {opacity: .4}

   to {opacity:}

 }

 var slideIndex = 0;

 showSlides();

 function showSlides() {

     var i;

     var slides = document.getElementsByClassName("mySlides");

     var dots = document.getElementsByClassName("dot");

     for (i = 0; i < slides.length; i++) {

        slides[i].style.display = "none";

     }

     slideIndex++;

     if (slideIndex > slides.length) {slideIndex = 1}

     for (i = 0; i < dots.length; i++) {

         dots[i].className = dots[i].className.replace(" active", "");

     }

     slides[slideIndex-1].style.display = "block";

     dots[slideIndex-1].className += " active";

     setTimeout(showSlides, 2000); // 切换时间为 2 秒

 }